Fluorescent light fixtures that enclose long tubular bulbs are the prevailing form of illumination in industrial and commercial spaces, and are also a popular light fixture in many residential spaces. The shape and configuration of tubular fluorescent bulb fixtures has not changed substantially since their initial introduction. "Flush-mount" fixtures, designed to be inserted into so called "drop ceilings," traditionally define a box-like sheet metal housing having a width of two feet and a length of four feet in the United States. This corresponds to the dimensions of standard one-foot square ceiling tiles. The housing typically holds three or four equally spaced tubular bulbs, each located within its own reflector well. Each reflector well is shaped, generally, like an elongated trough with the bulb seated near the lowest point of the trough. Each end of the bulb is supported in a mounting bracket/connector that also makes electrical contact with a standard two-pin connector on each opposing end of the bulb. A ballast is connected in line between the building 120 VAC current source and the bulbs. The ballast generates a high frequency driving current is located beneath one of more of the reflector wells, or is located on the exterior of the housing The reflector troughs are often metallic, and are painted gloss-white. The opening of the housing faces downwardly to allow light to escape. The rim defining the opening sits flush with the plane of the ceiling, and the opening is either open, or covered with a prismatic diffuser grate formed from translucent plastic.
Similar fluorescent bulb fixtures are used with minor modifications in a so-called "surface-mount" arrangement in which the housing stands out from the ceiling surface, and is fully exposed. In both surface-mount and flush-mount/recessed configurations, the housing is deep and generally bulky. The reflectors tend to absorb a substantial amount of incident light. The arrangement of the bulbs and reflectors also tends to cause light to be transmitted from the bulbs back into the housing. Some light is even reflected back into the bulbs themselves. Many of these three and four-bulb fixtures exhibit a reflected light efficiency of 75% or less. In other words, only 75% of the light generated by each of the bulbs is actually projected out of the opening to where it is needed. 25% or more of the generated light is absorbed by the fixture housing or the bulbs themselves.
Various programs administered by the United States government and public utilities have put forth standards that call for lighting fixtures having higher efficiencies. Accordingly, it is an object of this invention to provide a light fixture that projects light from fluorescent tube bulbs into a space more efficiently and that ensures that a larger proportion of light generated by the tubular bulbs is transmitted to the workspace. It is desirable that this fixture exhibit a less-bulky and/or lower profile that enables mounting on or within ceilings having lower clearances.